Moore, now 56, spoke with Diane Sawyer about some of the most harrowing details of her new book, Inside Out, on Good Morning America.
One of the most shocking anecdotes she shared was that when she was a teenager, after years of moving around the country, her mother Virginia King began taking her to bars so that they together would get attention from men.
Moore recalled how after one outing, she returned home to find an older man who had a key to their home. She said he raped her then afterwards asked: 'How does it feel to be wh***d out for $500?'
'It was rape and a devastating betrayal,' she wrote in the book.
Asked by Sawyer if she thought she was pimped out by her mother, she said: 'I think in my deep heart, no. I don't think it was a straight forward transaction but she still did give him the access and put me in harm's way.'
Moore was born in New Mexico but her biological father left her mother before she was born.
.@GMA EXCLUSIVE: “I made up about that that I wasn’t wanted … I didn’t deserve to be here.” @justdemi speaks to @DianeSawyer about dealing with her parents’ alcoholism and learning the man she knew as her father was not her biological dad. https://t.co/XfiCga6CV7 pic.twitter.com/dsqRJUs5u9— Good Morning America (@GMA) September 23, 2019
She was raised by her mother and her mother's second husband, Dan Guynes, who she thought was her real father until she was 13 and discovered her birth certificate.
Guynes was a newspaper advertising salesman and the small family moved around the country frequently.
Both he and her mother were alcoholics and her mother attempted suicide many times.
In her book, Moore recalls trying to save her mother's life at least once.
'I remember using my fingers, the small fingers of a child, to dig the pills out of her mouth,' she wrote.
By her teenage years, her mother and Guynes were no longer together and she and her mom had moved to Hollywood, where the rape happened.
She moved out shortly afterwards, aged 16, and launched her acting career.
As well as reflecting on her childhood, she recalled the troubles she had in her adult life including a 2012 collapse at a party where she combined a cocktail of drugs.
'I guess the fundamental question was how did I get here from where I started to what I'd experienced, how did i get here - I lost me.
'If I were to look back I would say I blinded myself and I lost myself,' she said of the incident.
She was not drinking but was partying with her daughter, Rumer, she said.
In the book, she says she took 'a hit of nitrous oxide' then smoked synthetic pot called Diablo. She also alleged that she broke her 20-year sobriety when her ex-husband Ashton Kutcher told her he did not believe in alcoholism and says he pressured her into threesomes.
She said she agreed to do them because she wanted to seem 'fun' to her much-younger husband but that they were a 'mistake'.
Moore also claims he cheated on her twice and that she miscarried a baby girl shortly after they began dating.
Kutcher's representatives did not immediately respond to DailyMail.com's inquiries on Monday morning.
In a statement to UsWeekly earlier this month, a spokesman for the star said: 'Ashton knew what was coming.
'He had a heads up on what is in the book.
'He's not mad or disappointed.
'This is Demi's truth, and he always felt sympathetic toward her.
'He knows her story and that her upbringing was difficult.'
The pair divorced in 2013 after eight years together.
Her book will be released on Tuesday.
It is dedicated to her daughters and to her mother.
After moving out of her mother's home, Moore started acting.
In 1980, she married her first husband, Freddie Moore. They were together for five years.
She married Bruce Willis in 1987 and the couple welcomed three children in their 13-year marriage. C
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